A satellite image taken on 18 March 2014 of an object spotted in the southern Indian Ocean by the Gaofen-1 high-resolution optical Earth observation satellite CNSA (China National Space Administration).

Here's an excerpt from our latest report on the current state of the search mission:

Poor visibility has hampered search efforts for debris that could be related to the missing Malaysia Airlines flight MH370 in the southern Indian Ocean, following new Chinese satellite images of a large object and separate sightings from a search plane of scattered debris.

“During Saturday’s search activities a civil aircraft tasked by Amsa reported sighting a number of small objects with the naked eye, including a wooden pallet, within a radius of five kilometres,” the statement said.

The Australian prime minister, Tony Abbott, had earlier announced on Thursday that a “credible” sighting had been made in the Indian ocean, about 2,500km south-west of Perth, based on satellite imagery of two large objects.

The series of announcement has seen a major concentration of effort to scour the southern Indian Ocean for the plane, which went missing over two weeks ago. Eight aircraft have been tasked by Amsa to undertake the search, and vessels from the United States, New Zealand, China and Japan are also aiding in the operation.

The Australian Maritime Safety Authority is delivering a press conference now. The General Manager John Young is speaking on the objects that were seen yesterday:

Today is really a visual search again and visual searches take some time, they can be difficult. Our plan is to continue seeking to make sight from the visual search, looking for the objects identified in the visual imagery.

Australia's Maritime Safety Authority has issued another update on how the search has progressed. The map below shows the search moving gradually in an easterly directions from the strong currents in the region.

Search area for Malaysian Airlines flight MH370 update on 23 March 2014.

My colleagues Alex Purcell, Fred McConnell and Mustafa Khalili have produced this short video explaining what we know about the missing Malaysia Airlines flight so far. The video shows how the search has developed and where efforts are now being focused

The Australian prime minister Tony Abbott, who is currently in Papua New Guinea, gave a press conference a short time ago where he reiterated that there did appear to be a number of small objects that were visually identified. He said he learnt about the possible sightings late last night:

Yesterday one of our civili a search aircraft got visuals on a number of objects in the Australia search zone.

[There were] a number of small objects, fairly close together within the Australian search zone, including as I understand it a wooden pallet.

Before we can be too specific about what it might be we need to recover some of this material.

The search effort has been joined today by two Chinese aircraft and two Japanese Orions.

The prime minister was then asked by journalists what the expert assessments were of the objects. He responded:

It’s still too early to be definite but obviously we have now had a number of very credible leads, and there is increasing hope, no more than hope…that we might be on the road to discovering what did happen to the aircraft.

It is important to stress that at this stage the objects identified by the observers have still not been recovered, despite other vessels undertaking a more thorough search of the area.

I’ve just spoken to Australia’s Bureau of Meteorology which advised the cold front that has arrived today in the southern Indian Ocean has led to poor visibility:

The Bureau of Meteorology continues to provide regular weather forecasts to support Australian Maritime Safety Authority’s search operation for the missing Malaysian Airlines aircraft, approximately 2500 kilometres southwest of Perth.

Drizzle and associated low cloud and reduction in visibility will continue through the weekend. Another cold front forecast to pass through the area today (Sunday) will bring rain, low cloud, and associated poor visibility.

The weather conditions will make the job of observers on board the search vessels more difficult.

Hagel assured his counterpart that he would “assess the availability and utility of military undersea technology for such a task and provide him an update in the very near future”, Kirby said in a statement.

Officials did not say precisely what equipment the Pentagon might provide but the US military has invested heavily in robotic technology designed for undersea surveillance against enemy submarines or torpedoes.

The United States Navy has a sophisticated undersea surveillance scheme known as the Sound Surveillance System (SOSUS). The early developments of undersea surveillance are outlined in this extract from the Navy’s Undersea Surveillance website that explores the history of undersea submarine surveillance in the 1950s:

In the months that followed, rapid progress was made in confirming that prominent low-frequency components were present in the submarine’s spectrum and that the sounds were of sufficient intensity to offer exceptional potential for long-range detection. At Sandy Hook, New Jersey, a small experimental system comprising a cable and a few hydrophones was installed in shallow water. The cable was terminated in a building owned by the U.S. Army. Despite high ambient noise due to the heavy shipping in the area, rudimentary range tests were conducted which demonstrated the feasibility of surveillance.

The first report on the project, which came to be called Jezebel, outlined the parameters for a Low-Frequency Analyzer and Recorder, or LOFAR. Bell Laboratories presented a working model of the spectrum analyzer with an analysis band of 1-1/2 Hz, operating in real time. Schemes were described for hydrophones, cables, delay lines and networks for simultaneously presenting multiple beams to achieve wide azimuth coverage. The first brass board model of a lofar was delivered in May 1951.

In July 1951, negotiations were completed with the British to acquire a seashore site at Eleuthera in the Bahamas. Six hydrophones were installed – three in 40 feet of water, two at 960 feet, and one at 1,000 feet. The first deep-water array was also installed off Eleuthera. It was a 40-hydrophone linear array, 1000 feet long, installed in 240 fathoms of water.

Some readers with an eye for detail have been pointing out that the search area appears to be moving in a vaguely eastern direction. While it’s possible there is other information being received that is impacting on the search zone, one reason for the gradual change is because of the strong currents that prevail in that region of the Indian Ocean, which would blow any debris towards the east. Janette Lindesay, an associate professor at the Fenner School of Environment and Society earlier explained:

Down in those kinds of latitudes the prevailing wind direction is westerly, which means they are blowing towards the east, but they don’t blow in perfectly straight lines.

It’s an area where we have basically a continuing series of low pressure weather systems that are steered by this westerly wind. They have strong winds associated with them, and the wind direction also changes between south westerly and north westerly depending on where you are in relation to these cold fronts.

So depending on what weather systems are passing through the area the wind directions will change, and that will make a difference to which way the wreckage, if it is a wreckage, will move.

The sort of rate of movements of the currents are around one to two nautical miles per hour. So just under four kilometres per hour is the rate that it is generally moving. So over a number of days it could move a hundred to a few hundred kilometres. If the wind picks up you can see an increase in the waves and you do get heavy waves in that area.

The other thing is that the ocean is really deep in this area. It’s between 3,500 to 4,000 metres deep so looking at the maps they’ve indicated the rough trajectory that the plane is on.

Australia’s Maritime Search Agency has just issued their 11th update for the search operation. It largely reiterates the same information from the previous release, and adds that they are continuing attempts to relocate debris spotted by one of their observers:

Search operations in the Southern Indian Ocean for the missing Malaysia Airlines aircraft will continue today in the Australian Search and Rescue Region.

The Australian Maritime Safety Authority (AMSA) reiterates this is a challenging search operation and continues to hold grave fears for the passengers and crew on board the missing flight. Several small objects of interest were identified by air observers on a civil aircraft in yesterday’s search.

A Royal New Zealand Air Force (RNZAF) P3 Orion aircraft with specialist electro-optic observation equipment was diverted to the location, arriving after the first aircraft left but only reported sighting clumps of seaweed.

The RNZAF P3 Orion dropped a datum marker buoy to track the movement of the material. Further attempts will be made today to establish whether the objects sighted are related to MH370.

Yesterday, China provided a satellite image to Australia possibly showing a 22.5 metre floating object in the southern Indian Ocean. AMSA plotted the position and it fell within yesterday’s search area. The object was not sighted during yesterday’s search.

AMSA has used this information in the development of the search area, taking drift modelling into account.

The release also adds that the search area has now been split into two zones:

Today’s search has been split into two areas within the same proximity covering 59,000 square kilometres about 2500 kilometres south-west of Perth. These areas have been determined by drift modelling.

A total of eight aircraft have been tasked by AMSA’s Rescue Coordination Centre to undertake today’s search activities. The civil aircraft are two Bombardier Global Express, a Gulfstream 5 and an Airbus 319.

One civil aircraft departed Perth for the search area just after 9am. Three other civil aircraft departed for the search area between 11am and midday. The United States Navy P8 Poseidon aircraft departed for the search area about 11am.

As the search continues on a predominantly visual basis in the Indian Ocean visibility is extremely significant. The last report received from Australia’s Bureau of Meteorology said that a further cold front was expected on Sunday:

The Bureau of Meteorology continues to provide regular weather forecasts to support Australian Maritime Safety Authority’s search operation for the missing Malaysian Airlines aircraft, approximately 2500 kilometres southwest of Perth.

Showers have eased following a cold front passing through the area on Thursday. Drizzle and associated low cloud and reduction in visibility are likely to continue. Winds are forecast to be relatively light, less than 15 knots, with swell easing below 2 metres. Little change to conditions is expected tomorrow.

Another cold front is forecast to pass through the area on Sunday.

This could hamper the search effort for Sunday if visibility in the area remains poor. A further update from the Bureau is currently being sought.

For our readers who may not have seen the Chinese satellite images that Australian authorities are now investigating, here's the object that the satellite captured.

A satellite image taken on 18 March 2014 of an object spotted in the southern Indian Ocean by the Gaofen-1 high-resolution optical Earth observation satellite CNSA (China National Space Administration).

Australia’s Maritime Search Agency has reiterated in a number of releases that they have tasked trained observers to try and visually identify wreckage from planes. The training for this sort of work by State Emergency Staff is intensive and requires formal certification. To give an indication of the kind of training and what sort of roles these observers can play, here’s an extract from a course curriculum of a series of outcomes that need to be met:

Operational briefing is obtained from relevant search and rescue authority

Aircraft is configured and loaded in accordance with policies, procedures and pilot-in-command instructions

Involvement in briefings is undertaken in accordance with policies and procedures and relevant documentation

Incident information is used to determine personal equipment needed for search operation

Scanning distance is identified and aircraft windows are marked in accordance with organisational procedures

Search briefing is reviewed en route to task area in accordance with policies and procedures

Impediments to effective observation techniques are identified and appropriate adjustments made in accordance with policies and procedures

Observation technique is applied in accordance with policies and procedures

Search equipment is operated to maximise sighting and identification effectiveness in accordance with policies and procedures

Sightings are reported and maintained in accordance with policies and procedures

Sightings are investigated in accordance with policies and procedures

Sightings are logged and communicated to the relevant search and rescue authority in accordance with policies and procedures

We can now confirm that the Chinese research vessel MV Xue Long has joined the search area. It was announced on 21 March that the vessel would be assisting the operation, and according to the most recent satellite data from Marine Traffic it is now in the search vicinity of the possible debris sighting. A map with up to date satellite information is publicly accessible, although not all vessels in the area will be transmitting.

For some background, the Xue Long is used as a supply vessel for China’s Antarctic Zhongshan Station. Most recently it was involved in a rescue operation in December 2013 to free another ship, the Akademic Shokalskiy, which had become trapped in ice off the Antarctic coast. The Xue Long subsequently became trapped in ice itself and was assisted by a United States icebreaker.

Chinese Antarctic research icebreaker Xue Long prepares to depart Fremantle Habour on 21 March 2014, as at least seven Chinese ships are reported to head for the southern Indian Ocean, where possible debris from a missing Malaysia Airlines MH370 plane has been sighted. Photograph: GREG WOOD/AFP/Getty Images

Good morning, I'll be continuing our live coverage of the search for missing Malaysia Airlines flight MH370. Here’s the Australian Maritime Safety Authority's last update on the search from Saturday, which includes an interesting note about a possible visual sighting of a cluster of small objects in the search area. An Orion that was subsequently tasked to examine the area couldn’t find anything from the visual sighting:

The Australian Maritime Safety Authority search operation for Malaysia Airlines flight MH370 has concluded for today. During Saturday’s search activities a civil aircraft tasked by AMSA reported sighting a number of small objects with the naked eye, including a wooden pallet, within a radius of five kilometres. A Royal New Zealand Air Force (RNZAF) P3 Orion aircraft with specialist electro-optic observation equipment was diverted to the location, arriving after the first aircraft left but only reported sighting clumps of seaweed.

The RNZAF Orion dropped a datum marker buoy to track the movement of the material. A merchant ship in the area has been tasked to relocate and seek to identify the material. The search area experienced good weather conditions on Saturday with visibility of around 10 kilometres and moderate seas.

The Royal Australian Air Force, the Royal New Zealand Air Force, two chartered civil aircraft and two merchant ships supported Saturday’s search effort in a 36,000 square kilometre search area in the Australian Search and Rescue Region. Since AMSA assumed coordination of the search on Monday 17 March, 15 sorties have been flown and more than 150 hours of air time has been committed by the air crews to the task.

Australia's prime minister, Tony Abbott, has been speaking to confirm overnight reports that a civilian aircraft searching for wreckage from MH370 has spotted debris in an area where a previous sighting has been made.

The Australian newspaper's website reports Abbott saying “a number of small objects very close together within the Australian search zone” had been reported.

The paper quoted him sayingthe debris included “as I understand it, a wooden pallet” but “before we can be too specific right now we do actually need to recover some of this material”.

“It’s still too early to be definite (that the debris is from an aircraft) but definitely we have now had a number of very credible leads and there is increasing hope — no more than hope — that we might be on the road to discovering what did happen to this ill-fated aircraft.”

Summary

A Chinese satellite has spotted an object 22 metres by 13 metres (72ft by 43ft) 75 miles from where an Australian satellite registered a similar object. The Chinese sighting came two days after the Australian sighting. Two Chinese Illuyshin aircraft arrived in Perth to help the search on Sunday.

Relatives of passengers of MH370 harangued Malaysian officials at a press conference in Beijing. Other relatives were asked to move from their hotel to make way for Ferrari staff who arrived in Kuala Lumpur for the Malaysian grand prix.

Another round of aerial searches of the southern Indian Ocean will begin when dawn breaks on Sunday. Crews based in Perth, western Australia, will be getting up shortly to prepare for the four-flight to the search zone.

Reuters report that the Australian Maritime Safety Authority said one of its aircraft reported sighting a number of "small objects" with the naked eye, including a wooden pallet, in the search area.A Royal New Zealand Air Force P-3 Orion aircraft took a closer look but only reported seeing clumps of seaweed. It dropped a marker buoy to track the movement. "A merchant ship in the area has been tasked to relocate and seek to identify the material," the authority said in a statement.

Since 17 March, planes have undertaken 15 sorties in the search area and "more than 150 hours of air time have been committed by the air crews to the task," Australian officials say.

This illustrates how difficult it is to search the areas as it takes eight hours to fly to and from the search area with two hours searching. If only 20 per cent of air time is used for searching that amounts to 30 hours of searching an immense area since Thursday.

Associated Press have been talking to some of the relatives of passengers of Flight MH370.

Wang Zheng, 30, an IT engineer, is waiting for news of his parents.

"We're exhausted. Why did the plane fly so far away? Are the people still alive? Is this new piece of information reliable? This is how I feel. We feel they're hiding something from us.

Biggest of all is the emotional turmoil I've been going through. I can't eat, I can't sleep. I've been dreaming of my parents every day.

Wang said he last spoke with his parents on the night of their departure, shortly before they boarded the plane. They told him they were busy filling out exit cards and would call him upon their arrival in Beijing.

I will stay here until they give me an answer. I am not leaving until I know for certain where my parents are. I am not leaving any time before that.

Nan Jinyan, 29, an engineer who designs equipment for heart patients, is the sister-in-law of missing passenger Yan Ling,

I'm psychologically prepared for the worst and I know the chances of them coming back alive are extremely small. I never imagined a disaster like this would befall our family, but life has to continue.

Like many of the relatives, Nan said that her helpless feelings were worsened by being almost entirely dependent on the media for news, and that she was deeply unhappy with what she called the vague and often contradictory information coming from Malaysia Airlines.

If they can't offer something firm, they ought to just shut up.

A girl reads some of the messages of hope and support for the passengers of the missing Malaysia Airlines MH370 at a mall outside Kuala Lumpur. Photograph: DAMIR SAGOLJ/REUTERS

Kate Hodal, the Guardian's south east Asia correspondent has pointed out that police were called when Chinese relatives of MH370 passengers harangued Malaysian officials earlier. This is from the New Straits Times.

Police were forced to intervene on Saturday as relatives of Chinese passengers aboard vanished Flight MH370 rushed towards Malaysian officials at a Beijing hotel, demanding answers over the fate of their loved ones.

"Government of Malaysia, tell us the truth! Give us back our loved ones!" shouted audience members at Saturday's briefing at the hotel attended by government officials. The hotel has hosted daily briefings for relatives from representatives of the airline.

"The Malaysian government is deceiving us. They don't dare to face us. The Malaysian government are the biggest murderers," a relative in the audience shouted, even though there is no evidence to suggest a government conspiracy.

As anger in the hall mounted, some relatives rushed towards the Malaysian officials but police intervened and the officials left the room.

"We can't bear it any longer," one woman said. "They're offering us compensation, but we've lost our entire families. This is China. They can't just tell us to come or go as they please. We're going to wait here. If they don't come, we're not leaving."

Based on the survey results, the World Shipping Council estimates that on average there are approximately 350 containers lost at sea each year, not counting catastrophic events. When one counts the catastrophic losses, an average total loss per year of approximately 675 containers was observed.

Total industry losses obviously vary from year to year, but these numbers are well below the 2,000 to 10,000 per year that regularly appear publicly, and represent a very small fraction of container loads shipped each year.2 Nevertheless, the industry continues to pursue measures to reduce the number of containers lost overboard to zero.

According to Reuters, Malaysian Defence Minister Hishammuddin Hussein said on Friday that searchers realised that time was running out. The "black box" voice and data recorder only transmits an electronic signal for about 30 days before its battery dies.

On the search near Australia, he said:

I am still quite concerned that - it's been two days - and yet the searches have not come out with any debris. I am not going to give up... My biggest concern is that we are not able to identify the debris, having to go back to the two corridors.

Transport minister Hishammuddin Hussein says six planes are searching an area of 10,500 square nautical kilometres in the southern Indian Ocean today although a cyclone warning has been issued in the southern corridor, with strong winds and rough seas forecast.

India, Cambodia, and Kazakhstan have confirmed their radar data has shown no sighting of the plane in their air spaces.

Australian rescuers have stepped up the search for Malaysian Airlines flight MH370 as pressure mounts to find the plane that vanished two weeks ago and has defied the best efforts of modern technology to track it down.

Six planes, including four Orion anti-submarine surveillance aircraft, joined the search on Saturday for debris from the aircraft over a remote stretch of the Indian Ocean 1,500 miles (2,500km) south-west of Perth.

Chinese, British and Australian naval ships were all headed to the same area where two floating objects – possibly plane wreckage – were picked out on satellite pictures.

With planes from China and Japan also expected to join the hunt, the sudden concentration of resources on the basis of such inconclusive evidence reflects growing desperation after 14 days of piecemeal progress.

There have been no sightings of interest since Thursday when Australia released the satellite photos taken on 16 March.